1. Field of the Invention
The present invention relates to a method for manufacturing a tape wiring board for a semiconductor package and, more particularly, to a method for manufacturing a tape wiring board, by imprinting a conductive polymer and forming a wiring pattern.
2. Description of the Related Art
Tape automated bonding (TAB) techniques may employ inner lead bonding (ILB) for inner connections. TAB techniques also may provide a reel-to-reel package assembly using a reel type tape wiring board. A package manufactured by the TAB technique is referred to as a TAB package. The TAB package may include a tape carrier package (TCP) and a chip on flex (COF). The TAB package may be thin and have fine pitch. A TAB package may be used in a wide range of applications, examples include in a watch, a calculator, a driver for a liquid crystal display and a micro-processor for a personal computer.
The tape wiring board also may be used for a semiconductor package such as a micro-BGA (μBGA) package and a chip on board (COB) package.
FIG. 1 is a cross-sectional view of a conventional tape wiring board 10. Referring to FIG. 1, a tape wiring board 10 may include a base film 11 and a wiring pattern 12 formed on the base film 11. A solder resist layer 19 may protect the wiring pattern 12, and may only partially cover it, exposing some of the wiring pattern 12 to connect with a semiconductor chip or an external terminal. The base film 11 may include a thermosetting polyimide tape. The wiring pattern 12 may include a wiring layer of Cu. The wiring pattern 12 may include an under barrier metallurgy (UBM) layer 13 formed on the base film 11, a wiring line 14 of Cu formed on the UBM layer 13, and a plating layer 15 of Sn surrounding the wiring line 14.
FIG. 2 is a flow chart of a conventional method 20 for manufacturing a tape wiring board 10.
Referring to FIG. 2, a base film 11 may be provided (21) and may include a thermosetting polyimide tape. The base film 11 may be formed from a polyamic acid solution by drum casting, drying and curing processes. An annealing process may improve the dimensional stability of the base film 11.
A UBM layer 13 may be formed (22), for example, on one surface of the base film 11. The UBM layer 13 may be made of materials that can adhere to the base film 11 and have metallic bondability with a Cu layer. For example, the UBM layer 13 may be formed using (Cr+Cu)/Ni by a sputtering method.
A Cu layer may be formed (23) on the UBM layer 13 at a predetermined thickness using the UBM layer 13 as a plating electrode.
The Cu layer may be patterned to form a Cu wiring line 14 (24) for example by a photolithographic process.
Specifically, an anticorrosive layer and an oxidation layer formed on the Cu layer may be removed by a soft etching process. The Cu layer may be etched to a thickness suitable for forming the Cu wiring line 14.
A photosensitive film may be applied to the Cu wiring layer. A portion of the photosensitive film may be removed through exposure and development processes. A portion of the Cu layer may be removed by an etching process, leaving a portion of the Cu layer to be a wiring line. The remaining Cu layer may be removed as well as the remaining photosensitive film.
A Sn plating layer 15 may be formed (25) and may surround the Cu wiring line 14. A Sn plating layer 15 may prevent oxidization of the Cu wiring line 14 and improve the bondability of the Cu wiring line 14 with an external terminal. Thus, formation of a wiring pattern 12 may be completed.
A solder resist layer 19 may be formed (26), for example by printing a solder resist. A solder resist layer 19 may protect the wiring pattern 12. The solder resist layer 19 may exclude a portion of the wiring pattern 12 to connect with inner and outer terminals.
The conventional method for manufacturing a tape wiring board may comprise providing a base film, forming a Cu layer, and patterning a Cu layer. These processes may even be performed in separate production lines.
Formation of a wiring pattern with Cu and a photolithographic may be quite complicated. The photolithographic may include a number of individual processes, which in turn may increase manufacturing time and cost.